This paper presents overview of 802.11 power saving mechanisms with priority to Distributed Coordination Function (DCF). In the 802.11 power saving mechanism, time is divided into beacon intervals. When each beacon interval starts, each node periodically wakes up for a time period called ATIM window. Synchronization is required between nodes so that they remain active at the same time. During ATIM window, nodes exchange control packets to determine whether they need to remain active for the rest of the beacon interval. The size of the ATIM window has a major marked effect on energy savings and throughput achieved by nodes. In the mechanism, the nodes that are involved in the data communication remain active and other nodes go into doze mode
